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Who throws a book?

A book thrown onto the stage narrowly misses U.S. President Barack Obama at a rally at Vernon Park in Philadelphia on Sunday, Oct. 10. A U.S. Secret Service agent, bottom right, appears to watch as the book flies over the stage. Obama, kicking off a busy week of campaigning, strove to energize his base on Sunday in order to minimize losses for Democrats in the November elections.

Saul Loeb/AFP-Getty Images

In this photo, the book can be seen flying behind Obama's right shoulder.

Saul Loeb/AFP-Getty Images

The book continues on its path (top right).

Inquiring minds would like to know who hurled a book at President Obama on Sunday at a rally in Philadelphia. After looking at the photos, can you name the book?

The U.S. Secret Service spoke with the book-thrower and described him as over-exuberant. You can watch a video of the incident HERE.